Shackleton's whisky is back on ice, with the prime minister returning three bottles of century-old whisky to Antarctica last night.

"I think we're all tempted to crack it open and have a drink ourselves now," John Key joked to media and about 35 Scott Base staff at the hand-over ceremony.

"In a way, they are kind of a time capsule of what took place here 100 years ago."

He carefully plucked one of the precious bottles wrapped in yellow-aged tissue and symbolically handed it to former Antarctic Heritage Trust chairman Rob Fenwick. It almost completes a remarkable journey for the historic drop. Three years ago, trust conservators excavated five crates of liquor found buried in ice under the hut's floorboards that had been bought for Anglo-Irish polar explorer Ernest Shackleton's 1907-09 unsuccessful expedition to the South Pole.

Three crates contained Mackinlay's whisky and two crates of brandy but it was the whisky bottled in 1898 that sparked international intrigue.

One whisky crate was flown to New Zealand and its 11 whisky bottles carefully thawed.

Three bottles were flown to Scotland for scientific analysis by Scottish distillery Whyte & Mackay, the Mackinlay brand's owner.

Tiny samples were extracted by syringe through the bottles' stoppers to allow master blender Richard Paterson to create a replica blend, called Rare Old Highland Malt Whisky.

Once the 50,000 bottles sold out, they produced a second version, called The Journey, and are donating a portion of sales back to the New Zealand-based charity, which could equal almost $1.5 million. The original bottles will be returned to Shackleton's Cape Royds hut by March, where the other crates are back in their original spot.

Yesterday, Key spent a busy second day in Antarctica in -12°C weather, visiting some of New Zealand's science projects and its Crater Hill wind farm, which is providing power to New Zealand and United States' Antarctic bases on Ross Island.

The project has reduced New Zealand's fuel needs by 50 per cent and by about 15 per cent for the US, saving millions of dollars.

He was supposed to visit the South Pole yesterday but bad weather forced its cancellation.

However, there is a chance that visit will go ahead tomorrow with weather forecast to improve on the frozen continent.

"It's totally weather dependent. We'll take a look tomorrow and make a call on it," he said.